WICHITA - The National Weather Service has issued a winter weather advisory for much of western and central Kansas. Cities in the advisory area include Wichita, Hutchinson, Salina, Great Bend, Medicine Lodge, McPherson and El Dorado. State transportation officials say they have been preparing for the storm since Friday. KAKE News spoke with KDOT spokesman Tom Hein, who said KDOT crews began pre-treating highways Friday. Hein said almost all road surfaces maintained by the state have been treated, in preparation for the storm's possible mixture of snow and freezing rain, paired with the potential dangers of New Year's traffic.